Circulating water channel



Aug. 21, 1945. ACIA. LEE 2,382,999

l CIRCULATING WATER CHANNEL Filed Oct. 6, 1945 HIS ATTORNEY Patented Aug. 2l, 1 945 UNITED N STAT- s PATENT .ol-FICE `(Ggranted under the act of MarchA 3, 1883, as

.amended April 30, 1928`370 O. G. 757) The invention relates to improvements in hydrodynamic testing apparatus andmore specically to a` circulating water channel for' testing ship models and performing other hydraulic experiments. j

It has been common practice to tow` scale models of ships, boats and special nautical devices throughstill Water in relatively long testing basins for the purpose of improving the design of such equipment. When a towing carriage is used, itis first accelerated to the desired speed at the beginning ofthe test run, and it must be brought to a stop before the end of the testing basin is reached. Since the actual test period is relatively short, it is usually necessary towmake numerous test runs in order to secure the desired performance data. While accurate results may be obtained by the towing method, the length ofthe that their thrust is counteracted by the Weight of the-propeller,` shaft and motor assembly.`

A' further object is to provide a deviceof the character described which isv so designed as to employ a plurality of large synchronous motorized pumps.

`An additional object of the invention is the provision of means for circulating Water through a vertically arranged loop having a channel in its upper portion, including propeller shafts so arranged as to not require water-tight packing.

. The invention also aims to provide means for converging the ow of water entering the water channel so asto produce a substantially uniform Velocity throughout the channel.

`Theinvention also has for an object to provide means for smoothing the surface of the stream of I water flowing into the channel.

test periods is limited by the dimensions of the I basin, and the loss of time between test runs is considerable. Also the inability to observe underwater phenomena from `above during towing, due to surface disturbances and lack of..illumination, has interfered with the making of certaintypes of tests.

It is, therefore, an important object ofthe present invention to providea circulating water channelfioi" continuously testing scale models of ships, boats andnautical devices. l

Another important object of the invention'is to provide meanspermitting the making of visual observations and photographs `from the side or from below the object being tested.

Still another important object is to provide a testing device of the character described whereby y the varioushydrodynamic vforces `exerted on the object under test may` be measured by methods similar to those utilized fin conventional towing basins.

Another object of the invention is to provide a water channel lwith means for producinga continuous"` uniformly. iiowing` stream of"water through the channel. A o

A further object is the provision"` of a circulating water duct forming a loop in a vertical plane with a water channel intheupper portion of ,the loop.

Yet another object resides in the provision of apparatus of the character described'which is "so arranged as to require a, relatively small amount;

of power for its operation and` wherein a plurality `of motors is used.

A stm further object of the intention is to provide means for circulating water through the channel including propeller pumps so arranged tev Other objects and advantages of the invention `will become apparent during the course of the following detailed description, taken in connection with the, accompanying drawing, forming a part of this specification, and in which drawing,`

I Figure 1` is .a top plan view of the apparatus.

Figure 2 is a vertical longitudinal sectional view` of the apparatus, taken substantially on the line 2-2 of Figure 1. f

Figure 3 is a lfragmentary horizontal sectional view taken substantially on the line 3-3 of Figure 2.

lIn the drawing, which for the `purpose of illustration shows only a preferred embodiment of the invention, and wherein similar reference characters denote correspondingV parts throughout the severalviews, the numeral I 0 generally designates the hydrodynamic testing apparatus, comprising a duct II forming a loop in a vertical plane and lincluding a` substantially horizontal water channel section I2 in the upper portion of the loop.`

This water channel section I2 comprises a at and essentially horizontal bottom wall I 3 provided Withltransparent watertight observation panels I I4, and spaced parallel upright side walls I5, I6,

provided with transparentwatertight observation panels I1.

. `Extending downwardly from the outlet end of the `water channel section I2 is a vertical pump and diffuser section I8 bisected by a central vertical partition I9 forming a pair of passageways 20, 2 I. This partition `I9 at its upper portion divides the outlet end of the Water channel section `and is provided with any suitable leading edge 22. In` the example shown, the leading edge 22 includes a wedge shaped upper portion and a rounded lower portion.

Extending downwardly through the outlet end of the water channel and into the passageways 20, 2| of the pump section are propeller shafts 23, 24 provided with conventional adjustable pitch propellers 25, 26. Fixed in the passageways 20, 2| subjacent the propellers, are radial- 1y disposed diffuser vanes 21 supporting stationary hub-like fairwaters 28 in which the` lower ends ofthe propeller shafts 23, 24 are journaled.

Mounted on a suitable platform 29 above the outlet end of the channel are synchronous constant speed electric motors 30, 3|-,.havingA vertical driveshafts 32 fastened to the upper ends of the propeller shafts at flanges v33. The. motors are arranged to drive the propellers. in opposite directions as indicated by the arrows in Figure 1.

The upper portion of the loop includesa. tubutlar nozzle section 34 for directing. a substantially uniformly iiowing stream of water into the inlet end of the water channel section I2. This nozzle section 34 is of a width equal' to that of the water channel section |22', but vertically, it: isl enlarged and tapers toward the inlet end of the water channel section I2'. Aslshown in Figure 2, the bottom of this nozzle section I3 includes a horizontal wall 35 and a wall 36 inclining. upwardly toward'the bottom wall. I3-I of the water channel. The top'of the nozzle section includes a slightly domed wall 31S provided with a valve controlled vent pipe 38', and; a'downwardly inclining wall 39 terminating in a transverse edge 40 below the top of the inlet endl of theY water channel section |21 Pivoted to the: transverse edge 4U, as by a waterproof hinge 4|, isa nap 42 provided withl means, such asv the worm 431 and sector 44, for setting the flap 42i in. any one of a plurality of positions of adjustment.

Extending between the lower end ofthe pump and diffuser section i8 and thel vertically' enlarged inlet end ofthe nozzle section- 34' are horizontal and vertical' return ducts 45, 45, respectively. The return duct 45- is of uniform crosssectional area and preferablyy is'sl'ightl'y' downwardly inclined toward a valve*controlled drain pipe 41.

In order to facilitate uniform flow of` water around the loop, suitable sets 48--51 of curved vanes may -be fitted in the elbows joiningthe horizontal and vertical lengths'v of the loop. In addition, a honeycomb vane assembly 52 may be xed in the vertically' enlarged nozzle lsectionl 34, to equalize the flow of water therethrough.

A plurality ofwater-tight releasable manhole closures 53 are provided to facilitate access to the interior of the loop, and a valve-controlled drain pipeV 54 is placed in the bottom wall'l I3 so that the water channel section may be emptied. The discharge end of the water channel section is provided with an inclinedsafety screen 55.

Merely for the purposes of: illustration', I have shown diagrammatically in` Figure 2, a transverse bridge member 56" carrying a dynamometer 51 operatively connected to a ship mod`el 58, as by suitable linkage 59, but it vwill be readily understood that a more elaborate form of bridge carrying any desired number and type of meters may be employed. Although the testing' apparatus may be of any Idesired size. at' present I. prefer to provide a circulating water channel large enough to test 20 to 30 footmodels and to provide a special buildings!! having floors at convenient levels so as to expedite the workY of the operating personnel.

above the surface 6| of the stream is at least as great as the capacity of the vertically enlarged nozzle section 34 above the level of the top 62 of the water channel section. Thus, by lllng the loop with water up to the top B2 of the water channel and then withdrawing the air in the upper portion of the nozzle section 34 through the pipe 38,Y as by a suitable suction pump (not shown), sucient water from the channel section |2 may be transferred to the nozzle section 34 to completely fill the upper portion thereof.

111 order to assure good underwater visibility of the object being tested, a conventional filter plant (not shown) is connected to the loop so as to remove any foreign material therefrom- The operation of the apparatus will now be described; When the motors 30, 3| are energized, the propellers 25, 26 rotate in opposite directions so as to circulate the water through the loop in a counter-clockwise direction, as viewed in Figure 2. .The radially disposed diffuser vanes 21 subjacent the propellers tendto prevent swirling of the water in the passageways 2.0, 2|. The head of water maintained in reserve in the upperl portion of the nozzle section permits thev water to flow uniformly and at a high velocity through the channel section l2. In order to compensate for variations in the head of waterl between the inlet and outlet ends of the waterchannel at different` operating speeds, a suitabley quantity of water is drained from or added to the loop, depending on whether the operating speed is increased or decreased. The pivoted a'pf42 maybe adjusted to a positionv wherein any ripples on the surface of the stream are reduced' to a minimum.

Variousv changes may be made in the form of invention herein shown and described withoutV departing from the spirit of the invention or the scope of the following claims.

Thisy invention may be manufacturedA and/or used by or forv the Government of the United States of America without the payment of any royalty thereon or therefor. j

I claim:

1. In testing apparatus of the character described, a duct forming a loop in a vertical plane and including a substantially horizontal open water channel section in the upper portion of the loop and a vertically disposed tubular sectionextending downwardly from the channel section, said loop being adapted to contain water below a given level in the channel section, a propeller shaft extending downwardly through the open water channel section into the tubular section and thus intersecting said water level so asto not require a shaft packing at the zone of entrance of the shaft into the water, a propelleriixed o n the shaft within the tubular section, and means disposed above said water level for driving the shaft.

2. In hydrodynamic testingl apparatus, a duct forming a loop in a vertical plane and including a substantially horizontal open water channel section in the upper portion of the loop, said channel section having a discharge end, a vertical tubular section extending downwardly from the dischargev end, said loop being adapted to contain water below a given level in the channel section, a vertical shaft extending through said discharge end into said tubular section and thus intersecting said water level so as tov not require a shaft packing atthe zone of entrance of the shaft into the water, a propeller on the shaft for forcing water downwardly through the tubular section,

. said duct decreasing a substantially horizontal open water channel in the upper portion of the loop, said channel having a discharge end, a vertically disposed tubular section extending 4downwardly from `said discharge end, said loop being water below agiven level in the channel, means dividing said tubular section into a plurality of vertical passageways, said dividing means including a vertically extending leading marginal edge at the discharge end of said channel for splitting the water entering said tubular section from said channel, said leading marginal edge including portions disposed above and below said water level and shapedto reduce turbulence and interference with the smooth flow of water in said channel, propeller shafts extending downwardly through the discharge end of the channel one into each of said passageways, propellers xed on said shafts one in each of said passageways, and individual motors for driving said shafts each in adirection such that said propellers force said water downwardly through said vertical passageways,

4. In hydrodynamic testing apparatus, a horizontal open water channel having an inlet end and means for directing a substantially uniform stream of water into said inlet end including a tubular duct communicating with said inlet end,

said duct being of a uniform width substantially equal to that of the water channel, the height of toward said inletend.

5. In hydrodynamic testing apparatus, a horizontal open water channel having an inlet end, a substantially flat bottom and upright sides, and means for directing a substantially uniform stream of water into said inlet end including a tubular duct of `uniform width communicating with said inlet end,` said duct havingupright sides aligning with the sides of the channel, a bottom inclining upwardly toward the :bottom 'of the channel and a top inclining downwardly toward the inlet end of the channel and terminating in an edge substantiallydetermining the height of said stream of Water in the channel.

6. In hydrodynamic testing apparatus, a water channel having an inlet end, means for directing a stream of water'into said inlet end, and means for smoothing the surface of said stream including a nap providing a horizontal edge for contacting the surface of said stream transversely of the direction of ow. i

`7. In hydrodynamic testing apparatus, a water channel having an inlet end-means for -directing a stream of water into said inlet end, and means for smoothing the surface of said `stream including a ap, means hinging the flap for movement of its free edge into'and out of contact with the surface of said stream transversely of the `direction of llow, and means releasably securing the flap in any one of a plurality of set positions.

8. In hydrodynamic testing apparatus, a water l channel having an inlet end, and means for diadapted to contain channel having recting a substantially smooth stream of water into said inlet end including a tubular duct having a top wall inclining downwardly toward the inlet end, said top wall terminating in a transverse edge at substantially the desired height of said stream in the channel, a flap pivoted along said edge, and means releasably securing the flap in any one of a plurality of set positions.

9. In a testingdevice of the class described, a duct forming a loop in a vertical plane and including asubstantially `horizontal open water channel in the upper portion of the loop, said channel having an inlet end, a tubular section communicating with said inlet end and including a top wall inclining downwardly toward said inlet end, means for propelling a stream of water :through said tubular` section in the direction' of 4said water channel, and means for withdrawing air from the upper portion of said tubular section so as to produce a higher water level in the tubular section than the water level in the open water channel.

10. In testing apparatus of the character described, a duct forming a loop in a vertical plane and including a substantially `horizontal water channel in the upper portion of the loop, said an inlet end, a tubular section leading to said inlet end 4and having a topwall `inclining downwardly toward said inlet end, said top wall terminating in `an edge below the top of the water channel for determining the height of a stream of water in the channel, the capacity of the channel abovethe surface of said stream being at least equal to the capacity of said tubular section above the level of the top of the water chan-` nel, and means for withdrawing air from the top of the tubular section.

11. The combination with a substantially horizontal open water channel having an inlet end,

of a tubular vertically enlarged nozzle of uniform i Width having a chamber communicating with saidinlet end, the upper portion of said chamber being disposed above a given level in said water channel, and means for introducing water into said chamber.

`CHARLES A. LEE. 

